Hi
continuing my autofocus adventures….

I’m running a set of images and have a limit saying refocus if HFR over 2.6 however the fits viewer is showing a HFR of 2.9 but it didn’t seem to do a refocus.

Anyone had this working, does it need multiple bad frames before it triggers?


Regards

Nigel

Hi Nigel,

in Ekos options, you can not only set the HFR limit to refocus, but also how often HFR is checked (every n frames). Then, every n frames, one extra focus frame is taken according to your settings in autofocus. The resulting HFR is relevant here. The HFR value calculated in the FITS viewer is a different thing and is good for comparing focus quality (and guiding quality and seeing!) of frames in a series. But for the refocus decision, the HFR is calculated exactly the same way it is during autofocus, with an extra frame taken and especially with the usually very short exposure (few seconds) that is used during autofocus.

CS, Bernd

Assuming you are running from the Scheduler you can configure how often the check is performed and add a tolerance...

I was actually using the capture module as I’ve yet to get to the level of needing a scheduler. I’m still at the ‘it’s clear, stick the gear outside, work dammit work’ stage rather than setting things up with it going after target’s while I’m sleeping in a warm bed stage.

So given I’m not using the scheduler when is it deciding that it needs to refocus? I watched it start doing it so I know it was doing things though the ‘activity/logging’ module didn’t actually show anything. If it’s not using the just taken images hfr is it taking a focus check image after each main image?

Oh ok. Well if you're running manually then its upto you when to refocus.

I think the idea of automating the refocus is for when you're running the scheduler and the gear is unattended so rather than capture hours of out-of-focus images you can configure a refocus.

IMHO, the best way to get a feel for how things work is to setup the simulators and practice doing stuff in daylight so you can make the best use of clear nights for imaging.

If you use the capture module to capture multiple images (I assume you do so and you don't capture each frame completely manually...), the focus check is applied after the same amount of frames given in the Ekos options "In-sequence HFR check".

Ok thanks that explains why it was kicking in so often.

Things just seem to be hidden all over the place in kstars…